The Chicago White Sox have agreed to terms on a two-year, $18 million contract with right-handed pitcher Kelvin Herrera, which includes a club option for 2021, and have designated left-hander Ian Clarkin for assignment. 
 
Under terms of the deal, Herrera will receive $8.5 million in both 2019 and 2020, while the White Sox hold a $10 million option for 2021 with a $1 million buyout.
Herrera, 29, combined to go 2-3 with a 2.44 ERA (12 ER/44.1 IP), 17 saves and 38 strikeouts over 48 relief appearances in 2018 with Kansas City and Washington. He recorded a 1.98 ERA (8 ER/36.1 IP) with 14 saves over 38 games in the first half, but was limited to 10 games after the All-Star Break due to a Lisfranc fracture in his left foot.
 
"Kelvin adds another veteran pitcher to our bullpen who has outstanding credentials and the proven ability to close games," said Rick Hahn, White Sox senior vice president/general manager. "He provides Ricky Renteria with another quality option in the late innings."
 
Herrera, 5-foot-10 and 205 pounds, was traded to the Nationals as part of a four-player deal on June 18 after posting a 1.05 ERA (3 ER/25.2 IP) with 14 saves over 27 games with the Royals.
 
Herrera, an American League All-Star in 2015-16, has gone 24-29 with a 2.82 ERA (144 ER/460.0 IP), 60 saves, 113 holds, 454 strikeouts and a 1.15 WHIP in 463 career games (all in relief) over eight major-league seasons with the Royals (2011-18) and Nationals (2018). He has appeared in 70-plus games four times in his career and has allowed fewer hits than IP in six of his seven full seasons in the majors.
 
A native of Tenares, Dominican Republic, Herrera appeared in 22 postseason games with Kansas City in 2014-15, going 2-0 with a 1.26 ERA (4 ER/28.2 IP), six holds and 38 strikeouts. He threw 3.0 scoreless IP in the deciding Game 5 victory over the Mets in the 2015 World Series.
 
Herrera owns a 1.50 ERA (5 ER/30.0 IP) in 31 career appearances at Guaranteed Rate Field, including a current streak of 10.2 scoreless IP over 11 outings.
 
Clarkin, 23, was reclaimed off waivers from the Cubs on November 26 after combining to go 4-5 with a 4.76 ERA (45 ER/85.0 IP) over 25 games (12 starts) with Class A Winston-Salem and Class AA Birmingham in 2018. 
With the moves, the White Sox 40-man roster remains at 40.